George w



(No Model.)

G. W. BRIGGS.

' PISTON'VALVE. No. 550,257. Patented Nov. 26, 1895.

I I I I ///l%! Ill/I1 WITNESSES. Igmmz. M WE" W gii? ANDREW BYERANAMSPnQTD-LMQWASHINGIOILDC.

UNITED STATES PATENT OFFICE.

GEORGE \V. DBIGGS, OF ELYRIA, OHIO, ASSIGNOR OF ONE-HALF TO MOSES BEAL, OF SAME PLACE.

PISTON-VALVE.

SPECIFICATION forming part of Letters Patent No. 550,257, dated November 26, 1895.

Applioationfiled March 25, 1893. Serial No. 467,540. (No model.)

To all whom it may concern:

Be it known that I, GEORGE WV. DRIGGS, a citizen of the United States, residing at Elyria, in the county of Lorain and State of Ohio, have invented certain new and useful Improvements in Piston-Valves and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to steam-cylinders and the slide-valves by means of which the inlet and outlet ports of said cylinders are opened and closed at the proper times.

The object is to provide a suitably-constructed cylinder and a slide-valve adapted to be contained in said cylinder and to combine the said cylinder, slide-valve, and the piston in such manner that the valve is automatically operated by the piston itself without any intermediate mechanism; and my invention consists in the construction and combination of parts hereinafter described, and pointed out in the claim.

In the drawings, Figure 1 is a horizontal longitudinal sectional view of the cylinder. Fig. 2 is a similar view with the piston and valve in position. Fig. 3 is a longitudinal vertical section of the middle part of the cylinder. Fig. 4 is a side view of the middle part of the cylinder, and Fig. 5 is a transverse sectional view in line 5 5 of Fig. 4.

Referring to the parts by letters, A represents the cylinder, which is provided near its middle with an exhaust-port a, and on opposite sides of said port with two inlet-ports a a which communicate with the steam-supply pipe G.

B B represent two steam-passages, which in the construction shown are formed in the walls of the cylinder A. Both passages are connected at two points with the cylinder and afford means of communication between two parts thereof. The passage B communicates through port I) with the crank end of the cylinder and through portb with a part of the cylinder which lies between the exhaust-port a and that inlet-port a which is nearer the head end of the cylinder. The passage B communicates through the port b with the head end of the cylinder and through the port 12 with the functions of these two passages are re-' versed.

D represents a cylindrical Valve, which lies in the cylinder A. It has two lips dd, the former of which is adapted to close the inletport a while the latter is adapted to close the inlet-port a, and both lips separate the exhaust-cavity F, which is formed by an annular groove d between them from the other parts of the cylinder between the two piston-heads. The end of a set-screwE enters the exhaustcavity and by engaging with the valve serves as a stop to limit the movement of the valve, thereby retaining it in such positions that the exhaust-port 0. always communicates with "the said exhaust-cavity.

The piston O is provided with two heads 0 c, which'are rigidly connected by the rod 0 This rodpasses loosely through the valve D. The two heads are such a distance apart that the ports a, a, 0. b, and b always lie between them. valve, which prevent the too close approach of the heads a c to the valve.

In the operation of the apparatus described, when the piston is about to move toward the head end of the cylinder, the valve is nearest the crank end thereof, in which position the port I) is open, so that steam which enters the cylinder through port a between the pistonheads passes through the passage B into the cylinder again between the crank end thereof and the piston-head 0. At the same time the port 19 communicates with the exhaust-space F, whereby the steam passes from the head end of the cylinder through the passage B into said exhaust-space, whence it escapes through port a and pipe f, which covers said port. When the piston has nearly completed its stroke, it strikes the valve and moves it toward the head end of the cylinder to the position shown in the dotted lines in Fig. 1, where the passage B communicates through (1 represent bosses on the ends of the v port I) with that part of the cylinder which is receiving steam through port a while passage B is in comm unication with the exhaust-space F, and the piston thereupon begins its movement toward the crank end of the cylinder.

It will be seen that the piston in moving in either direction strikes the valves at the proper time, thereby so moving it that the part of the cylinder toward which said piston is moving is disconnected from the exhaust system and connected with the live-steam supply, while the other end of the cylinder is connected with the exhaust and the livesteam supply thereto is cut off.

Having described my invention, I c1ai1n A steam cylinder A having an exhaust port a near its middle and two inlet ports a a on opposite sides of said exhaust port, and having also two steam passages B B formed in its wall,-the steam passage B being connected with the cylinder at two points, viz., near the crank end thereof and between the exhaust port and that one of the inlet ports which is nearest the other end of the cy'linder,-a1n1 the steam passage B being connected with the cylinder at two points viz. near the head, and between the exhaust port and that one of the inlet ports which is nearest the crank end of the cylinder, combined with a piston rod, two piston heads secured thereto, a slide valve fitted in said cylinder loosely surrounding the piston rod between the piston heads, said valve having between its ends an annular groove, and bosses d on the ends of said valve, substantially as and for the purpose specified.

In testimony whereof I atfix my signature in presence of two witnesses.

GEO. W. DRIGGS. 'Witnesses:

E. L. THURSTON, PAUL STEGER. 

